Effects of organic and other management practices on soil nematode communities in tea plantation: a case study in southern China

Abstract

Four major tea management practices (organic, pollution-free, conventional, and semi-natural) are employed in Chinese tea plantations at present. These practices can induce changes in the physiochemical parameters, microorganism community and enzyme activity in tea plantation soil. However, understanding of their effects on soil nematodes is still scarce. This study aimed to investigate whether and how different management practices affect the biodiversity, function, and structure of soil nematode communities in tea plantation habitats. The soil nematode community structures and ecological indices were determined from the soil samples collected more than 6 y after their respective farming practices were first applied, and different management practices did not greatly affect soil nematode community evenness or species diversity, but organic practice increased nematode trophic diversity, common species diversity, and species richness. Pollution-free practice considerably increased fungivorous nematodes, and both pollution-free and conventional practice decreased bacterivorous nematodes markedly in the subsurface layers of soil. Predator and omnivorous nematodes were found to be more abundant in semi-natural plantation. Organic practice was more sustainable and suitable for tea cultivation, with the greatest biodiversity, best nutrient conditions, higher and more stable C/N ratio and lower interference in the food web.

Effects of straw mulching practices on soil nematode communities under walnut plantation

“…Combined with the ecological indices BI, which is related to soil properties and decomposition pathways 24 , we found that higher CI value for the three straw mulching treatments appeared in the whole-plot coverage treatments ( all n ). Our results contrast with those of other studies, which found that bacterial-dominated decomposition pathways were the most common pathways 20 . This discrepancy could be explained mainly by the observed variations in the abundances of bacterivores and fungivores among the different coverage distances.…”

“…Moreover, this finding is also contrary to our first hypothesis that different straw mulching treatments would increase the number of soil nematodes. The reasons are as follows: on the one hand, phenolic acids enter the soil through the secretions of walnut roots and the decomposition of a large amount of straw residues, which results in an increase in phenolic acids in the soil and a decrease in the total number of soil nematodes and other nematodes 20 . On the other hand, straw mulching returns pathogenic bacteria and parasite eggs to the field directly.…”

Dynamics of Soil Nematode Communities Revealed Significant Variation in Greenhouse with Different Continuous Cropping Years

“…In order to obtain high yield and high quality of vegetable, farmers usually applied abundant organic and N fertilizer to greenhouse filed. However, high input of nutrition were not fully utilized by soil microorganisms and plants, the extra nutrition remained in the soil, thus lead to a series of soil problems such as soil degradation, salt accumulation and pH declining in greenhouse with long planting history [13,49-51]. A general conclusion that N fertilization caused the soil pH decreased while EC increased significantly, indicating that long-term inorganic N fertilization causes soil acidification and salinization [13,52-54].…”

“…However, high input of nutrition were not fully utilized by soil microorganisms and plants, the extra nutrition remained in the soil, thus lead to a series of soil problems such as soil degradation, salt accumulation and pH declining in greenhouse with long planting history [13,49-51]. A general conclusion that N fertilization caused the soil pH decreased while EC increased significantly, indicating that long-term inorganic N fertilization causes soil acidification and salinization [13,52-54]. The pH decrease may be resulted from the production of acidic metabolites came from the process of urea assimilation by soil microorganisms [55] and from the process of nitrification [56].…”

“…As the most abundant group of soil fauna, soil nematodes play important roles in the soil ecosystem, including the decay of organic materials and nutrient transformation. Because soil nematodes are sensitive to agricultural management activities [11-13], nutrient states and the soil environment [14], their populations and community structure are affected by soil disturbances. Therefore, soil nematodes are suitable indicators of soil health.…”